Deborah Heiligman’s captivating dual biography of the Darwins, Charles and Emma(Holt, 268 pp., $18.95), is one of the best young-adult books I’ve read since launching this site. This finalist for the 2009 National Book Award for young people’s literature lacks the problems of last year’s winner, What I Saw and How I Lied, among them a clash between its third-grade reading level and its sophisticated content. Good as it is, Charles and Emma isn’t a shoo-in: It’s up against books that include Phillip Hoose’s Claudette Colvin: Twice Toward Justice (Farrar, Straus & Giroux, 144 pp., $19.95), the true story of a 15-year-old whose refusal to give up her seat to a white passenger helped to integrate the buses in Montgomery, Alabama. I haven’t been able to put my hands on a copy, but I admired Hoose’s Perfect, Once Removed (Walker, 2007), a memoir of the October when his cousin Don Larsen pitched a perfect World Series game, and I hope to say more about both National Book Award finalists soon.